Typical hydraulic systems have a hydraulic reservoir (i.e. a hydraulic fluid storage tank) that stores excess hydraulic fluid that is used by the system. The hydraulic fluid is a working fluid that is typically used to drive hydraulic cylinders, pumps, hydraulic motors or other devices for performing desired operations. Typically the hydraulic systems will include a hydraulic pump to pressurize the fluid as it passes through the system to provide adequate power to drive the devices of the system. Additionally, hydraulic systems typically reuse the hydraulic fluid such that the hydraulic fluid is drawn from the storage tank passed through the system and then deposited back into the storage tank where it is held until it is reused by the system again.
To prevent debris or impurities from repeatedly passing through the system, prior art storage tanks, typically includes a return flow filter that may be either internal to the tank or external to the tank that filters the return fluid prior to the fluid being mixed with the rest of the clean fluid being stored in the fluid tank. Unfortunately, the primary filter is typically sized such that smaller particulate is permitted to pass through the filter media so that too large of a pressure drop is not created across the filter and such that the filter can accommodate the large quantity of hydraulic fluid passing through the hydraulic system.
Filtration of these smaller particulates has previously been effectuated by using a kidney-loop filtration system that is a secondary fluid flow loop that is strictly used to filter the fluid and is typically not in-line with the primary hydraulic system. These kidney-loop filtration systems require a second hydraulic pump to drive the fluid through the system. Unfortunately, the use of a second hydraulic pump is expensive and requires the ability to drive the second hydraulic pump making it difficult to integrate the kidney-loop system into the overall system. Typically, the filter elements for the kidney-loop systems require greater pressure to force the fluid through the filter elements.
The present invention relates to improvements over the current state of the art.